A = {1 ; 3 ; 5 ; 7 ; ...}

B = {14 ; 17 ; 20 ; 23 ; 26 ; 29}

\(a,C=\left\{0;5;10;15;20;25;30\right\}\\ b,x^2+3x-4=0\\ \Leftrightarrow x^2-x+4x-4=0\\ \Leftrightarrow x\left(x-1\right)+4\left(x-1\right)=0\\ \Leftrightarrow\left(x-1\right)\left(x+4\right)=0\\ \Leftrightarrow x-1=0.hoặc.x+4=0\\ \Leftrightarrow x=1.hoặc.x=-4\\ Vậy:D=\left\{-4;1\right\}\)

C= {3, 7, 11, 15, 19}

BẠN ĐÁNH DẤU MÌNH ĐI

thankss các bn

a)

A={0; 1}

B={0; 3}

b) A∩B={0}. A∪B={0; 1; 3}. A\B={1}

a) Ta có :

12 = 2² x 3

18 = 2 x 3²

=) BCNN ( 12; 18 ) = 2² x 3² = 36.

=) BC ( 12; 18 ) = B ( 36 ) = \(\left\{0;36;72;108;...\right\}\)

b) A = \(\left\{3;9;15;21;27\right\}\)

C = {6; 7; 8; 9; 10}

A={1,3,5,....}

B={11,14,17,20,23,26,29}

a) \(2x^3-3x^2-5x=0\)

\(x\left(x+1\right)\left(2x-5\right)=0\)

\(\Rightarrow\left[{}\begin{matrix}x=0\left(L\right)\\x=-1\left(TM\right)\\x=\dfrac{5}{2}\left(L\right)\end{matrix}\right.\)

\(A=\left\{-1\right\}\)

b) \(x< \left|3\right|\)\(\Leftrightarrow-3< x< 3\)

\(B=\left\{-2;-1;1;2\right\}\)

c) \(C=\left\{-3;3;6;9\right\}\)

a) \(A=\left\{x\in Z|2x^3-3x^2-5x=0\right\}\)

\(2x^3-3x^2-5x=0\)

\(\Leftrightarrow x\left(2x^2-3x-5\right)=0\)

\(\Leftrightarrow x\left(x+1\right)\left(2x-5\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=-1\\x=\dfrac{5}{2}\left(loại\right)\end{matrix}\right.\)

\(\Rightarrow A=\left\{0;-1\right\}\)

b) \(B=\left\{-2;-1;0;1;2\right\}\)

c) \(C=\left\{-3;3;6;9\right\}\)